It's possible. I looked through several seed catalogues to see if I could find anything like it, and the only thing close was Amaranthus tricolor, also called "summer poinsettia", reaching a height of 4-5 feet. I didn't think that that was what the sign at the nursery said, but it's possible.

Now having invoked the Power of Google, we're reasonably convinced that it is indeed Amaranthus tricolor, also called "Joseph's coat". And we still haven't planted them yet, because it turns out we did have enough plants to fill all our space, so we have to dig a new bed for them.

If they make it. Putting them in the ground has been delayed by rain (especially since digging the new bed is going to be work, and in the meanwhile two of the six look pretty close to dead, and none of them are the picture of health.

But I've noticed that plants can be resilient if treated right. Hopefully it will dry out enough to get them in the ground in the next day or two.